Journal ArticleDOI
Organic farming: challenge of timing nitrogen availability to crop nitrogen requirements.
X.P. Pang,J. Letey +1 more
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In this article, the ENVIRON-GRO computer model was used to analyze the impact of N and irrigation management effects on crop yield and N leaching in organic farms.Abstract:
Groundwater has become increasingly degraded by NO 3 , and this degradation has been partially attributed to the use of commercial inorganic N fertilizers. Conversion from conventional fertilizer management to organic farming has been proposed as a means to reduce groundwater degradation. Matching soil inorganic N supply with crop N requirement on a temporal basis is important to achieve high yield and low water degradation. Dynamics of N mineralization from two manures and N-uptake dynamics for two crops were derived from published data, and multi year simulations were done using the ENVIRON-GRO computer model, which accounts for N and irrigation management effects on crop yield and N leaching. The temporal N-mineralization and N-uptake curves did not match well. The potential N uptake for corn (Zea mays L.) exceeded the cumulative mineralized N during a significant period that would cause reduced yield. Wheat (Triticum aestivum L.) has a low and flat N-uptake peak, so that the cumulative mineralized N met N demand by wheat during the growing season. A crop with a very high maximum N-uptake rate, such as corn, would be difficult to fertilize with only organic N to meet peak demands without excessive N in the soil before and after crop growth. In order to satisfy crop N demand, a large amount of manure, which would leave much N or subsequent leaching, must be applied. It took two or more years after conversion to organic sources of N to reach maximum yield because of carryover of unmineralized manure and accumulation of mineralized N after crop uptake which was not completely leached during the winter. High initial applications to build up the organic pool followed by reduced inputs in subsequent years would be appropriate.read more
Citations
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Journal ArticleDOI
Comparing the yields of organic and conventional agriculture
TL;DR: A comprehensive meta-analysis is used to examine the relative yield performance of organic and conventional farming systems globally, and shows that, overall, organic yields are typically lower than conventional yields.
Journal ArticleDOI
Developments in breeding cereals for organic agriculture
Martin Wolfe,Jörg Peter Baresel,Dominique Desclaux,Isabelle Goldringer,S. P. Hoad,Géza Kovács,F. Löschenberger,Thomas Miedaner,Hanne Østergård,E. Lammerts Van Bueren +9 more
TL;DR: The need for increased sustainability of performance in cereal varieties, particularly in organic agriculture (OA), is limited by the lack of varieties adapted to organic conditions, and the needs for breeding are reviewed in the context of three major marketing types, global, regional, local, in European OA.
Journal ArticleDOI
Characterizing nitrogen use efficiency in natural and agricultural ecosystems to improve the performance of cereal crops in low-input and organic agricultural systems
TL;DR: In this paper, the authors assess genetic and environmental factors that could assist breeders in improving crop performance in low-input and organic farming systems by examining NUE in natural and agricultural ecosystems.
Journal ArticleDOI
Closing the Global Energy and Nutrient Cycles through Application of Biogas Residue to Agricultural Land – Potential Benefits and Drawback
TL;DR: Anaerobic digestion is an optimal way to treat organic waste matter, resulting in biogas and residue, and utilization of the residue as a crop fertilizer should enhance crop yield and soil fertility, promoting closure of the global energy and nutrient cycles as mentioned in this paper.
Journal ArticleDOI
Effects of different manuring systems with and without biogas digestion on soil mineral nitrogen content and on gaseous nitrogen losses (ammonia, nitrous oxides)
Kurt Möller,Walter Stinner +1 more
TL;DR: In this article, the effects of biogas digestion on soil mineral N (SMN) content in spring and autumn were assessed and compared to compare NH3 volatilization following superficial application of different manures to a cereal crop.
References
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Journal ArticleDOI
On the validation of models
TL;DR: In this paper, it is suggested that the correlation coefficieness between observed and simulated variates is not as good as observed variates, and that correlation can be improved.
Journal ArticleDOI
Nitrogen in crop production: An account of global flows
TL;DR: In this article, it was shown that despite some significant local and regional losses, the world's agricultural land accumulates N. The best evidence suggests that in spite of some significant localized losses, agricultural land still accumulates about 85% of the reactive N in the world.
Journal ArticleDOI
Fundamental Differences Between Conventional and Organic Tomato Agroecosystems in California
TL;DR: Differences between the agroecosystems were sufficiently robust to be distinguished from environmental variation and suggest that biological processes compensated for reductions in the use of synthetic fertilizers and pesticides.